1. Field of the Invention
This invention relates in general to equipment for removing refrigerant fluid from refrigerated air systems, cleaning the fluid and storing it for later use.
2. Description of the Prior Art
Many refrigerated air systems, such as air conditioning systems, utilize chloroflurocarbons (CFC's) as the refrigerant. Scientists believe that the release of CFC's into the atmosphere tends to destroy the ozone layer in the earth's stratosphere. Environmental concerns and governmental regulations dictate that as little as possible of CFC's be released into the atmosphere.
When performing maintenance on refrigerant systems, often the refrigerant fluid must be removed. In the past, repairmen would vent the gases to the atmosphere. Now, manufacturers market equipment to recover the refrigerant rather than vent it to the atmosphere.
The prior art refrigerant recovery equipment has an inlet for connection to the air conditioning system for receiving refrigerant. An expansion valve expands any liquid refrigerant to gas. A compressor will compress the gas, which then flows to a compressor. A condenser condenses the gas to a liquid, and stores it in a storage container for later use. The equipment has filters for filtering metal particles and other impurities as the refrigerant flows through the recovery equipment. The equipment has a recycle mode to recycle the refrigerant from the storage container back through the recovery equipment for further filtering.
Air conditioning systems utilize a compressor which requires oil. While recovering the refrigerant, some of the oil will be drawn out into the recovery system. The recovery equipment has a low pressure oil trap or separator on the suction side of the recovery equipment compressor for trapping the oil drawn in from the air conditioning system. The amount of oil recovered will be measured. This amount of oil will be re-introduced into the air conditioning system when repaired to assure that the compressor operates with the proper amount of oil.
The compressor of the recovery equipment also has a compressor that requires oil. Some of this oil will be released as a mist into the high pressure gas flowing from the compressor. A high pressure oil trap locates on the discharge side of the compressor. The high pressure oil trap separates oil from the refrigerant gas. It has an oil line that leads back to into the compressor suction. A float allows the compressor to draw oil back in when the level in the high pressure oil trap exceeds a minimum.
Normally, some of the oil mist in the regrigerant gas being recovered will flow past the low pressure oil separator. This oil will be drawn into the compressor. This may result in the recovery system compressor operating on more oil than it needs. Some of the excess oil will be discharged out the high pressure side of the compressor. However, this excess oil will be trapped by the high pressure oil trap and drawn back through the oil line into the compressor.
Excess oil can be damaging to the compressor. When the compressor is off, there is no way for any excess oil to drain out of the compressor if the high pressure oil trap valve is closed.